package com.hjc.springbootmovies.intercaptors;

import com.hjc.springbootmovies.entity.ModelUsers;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Created by IntelliJ IDEA.
 * User: HJC
 * Date: 2019/12/4
 * Time: 15:48
 * To change this template use File | Settings | File Templates.
 */
@Component
public class UserHandler implements HandlerInterceptor{
    /**
     * 预处理回调方法，实现处理器的预处理
     * 返回值：true表示继续流程；false表示流程中断，不会继续调用其他的拦截器或处理器
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        ModelUsers modelUsers = (ModelUsers) request.getSession().getAttribute("users");
        if (modelUsers == null) {
        return false;
        }else{
            return true;
        }
    }
    /**
     * 后处理回调方法，实现处理器（controller）的后处理，但在渲染视图之前
     * 此时我们可以通过modelAndView对模型数据进行处理或对视图进行处理
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request,response,handler,modelAndView);
    }
    /**
     * 整个请求处理完毕回调方法，即在视图渲染完毕时回调，
     * 如性能监控中我们可以在此记录结束时间并输出消耗时间，
     * 还可以进行一些资源清理，类似于try-catch-finally中的finally，
     * 但仅调用处理器执行链中
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        //nothing
        HandlerInterceptor.super.afterCompletion(request,response,handler,ex);
    }
}
